We have had the same problem in rolling out Qlik Sense in our organisation. Certain small latops seemed to have the issue.
There were a few work arounds
1. the guys tried clicking the blank space where it could be and sometimes it opened up. Not ideal but got him working.
2. make sure you have your zoom set to 100% not 120% or something like that.
3. Going into the machine settings and updating the device (latst drivers etc...) helped one user fix his issue.
I have raised a support ticket and it is something Qlik are investigating and should have a resolution next release.
As a temporary workaraund you can always start your Qlik sense desktop just like you doing now and once you logged in to it open your web browser (Chrome, IE, Edge, Mozilla, Opera...Safari.. whatever...) and put this url:
this will basicly open your QlikSense desktop in your web browser, hense you should not have any scaling issues.
keep in mind that Qlik Sense desktop needs to run in background.